Deposition of GdSmTi Coating for Corrosion Control of SS 316L in Bio-Field

Abstract

The corporation of rare earth metals (lanthanides series) with other metals gives good properties in different fields, such as protecting the metallic surface from corrosion risk. In this work, the investigation on adding gadolinium (Gd) and samarium (Sm) as rare metals to bio-inert titanium (Ti) as transition metal was done to protect stainless steel (SS 316L) as bio metallic implant which is used in biofield because of its excellent mechanical properties, low costs, biocompatibility, inertness, and mechanical properties, chemical stability, workability, and high corrosion resistance. The corporation was done through coating using direct current (DC) sputtering technique from the target of these metals mixture to measure some properties. The surface characterization by X-ray diffraction (XRD) gave many phases represented by different GdxNiy in addition to the Ni3Ti phase and Ni5Sm phase. The scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDS) results showed the distribution of coating metals as a dense thin film with a good ratio of coating metals; this dense film gave lower surface roughness as illustrated through Atomic force microscopy (AFM) examination from 25.20 nm for the uncoated sample to 15.12 nm for the coated sample with a reduction in the hardness from 187 HV for the uncoated sample to 119 HV for the coated sample as well as increasing contact angle test (wettability) from 90° for base stainless steel surface to 117.723° for coated surface, these results enhanced the compatibility with giving good resistance from corrosion test, with achieving protection efficiency equal to 99.02%.